Time-reversal checkpointing methods for RTM and FWI
Time-reversal checkpointing methods for RTM and FWI
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DOI：
10.1190/geo2011-0114.1
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发表时间：
2012-07
期刊：
影响因子：
3.3
通讯作者：
J. E. Anderson;Lijian Tan;Don Wang
中科院分区：
文献类型：
--
作者：
J. E. Anderson;Lijian Tan;Don Wang
时间域地震模拟可以作为逆时深度偏移和全波形反演的基础。这些应用需要将正向模拟状态与伴随模拟状态在时间上互相关联，因此需要能够以时间反向顺序访问正向模拟的每个时间步长。这需要为所有时间保存所有正向状态(这可能需要比计算机系统上对于许多感兴趣的问题通常可用的更多的存储器)，或者需要检查点信息并根据需要快速重新计算正向模拟状态的能力。以前的工作已经提出了如何通过优化选择哪个正向模拟时间步长到检查点来实现后一种方法，从而能够最有效地重用内存缓冲区并最大限度地减少重新计算。在假设进行时间互相关所需的信息小于从给定时间步长重新开始模拟所需的信息的情况下，可以进一步改进内存使用和重新计算之间的最佳权衡。对于许多感兴趣的地球物理问题，这一假设是正确的。这种修改可以减少内存需求和重新计算时间。测试实例应用于各向同性弹性逆时偏移和各向异性粘弹性全波形反演。
Time-domain seismic simulation can form the basis of reverse time depth migration and full-waveform inversion. These applications need to temporally crosscorrelate a forward simulation state with an adjoint simulation state and therefore need to be able to access each time step of a forward simulation in time-reverse order. This requires saving all forward states for all times (which can require more memory than is typically available on a computer system for many problems of interest), or the ability to checkpoint information and rapidly recompute forward simulation states as needed. Prior work has suggested how to do the latter by optimally choosing which forward simulation time steps to checkpoint, thereby enabling the most efficient reuse of memory buffers and minimizing recomputation. The optimal trade-off between memory usage and recomputation can be further improved under the assumption that the information needed to do temporal crosscorrelation is smaller than the information required to restart a simulation from a given time step. This assumption is true for many geophysical problems of interest. The modification can yield a reduction in the memory requirement and recomputation time. The tested examples applied to isotropic elastic reverse time migration and anisotropic viscoelastic full-waveform inversion.